Recent Advances in Integrating 1D Nanomaterials into Chemiresistive Gas Sensor Devices

There is rapid growth in the global gas sensor market driven by new regulations for industrial emission control and residential environments and increasing demand for portable devices. Nanosensors promise to be the next generation gas sensors for the direct detection of chemical species due to their ultrahigh sensitivity, fast response, ultralow weight, and low power consumption. However, transitioning nanosensors from basic research or prototype projects to commercial products encounters two major technical challenges: difficulty in scale up and inability to demonstrate real-world use in changing humidity and temperature conditions. The advances in addressing these two technical challenges in recent literature are surveyed. The most common 1D nanomaterials in R&D for gas sensing, metal oxides, and carbon nanotubes, as well as less common metal nanowires and psudo-1D crystals made from charge-transfer complexes (CTCs) are included. This review delves into the specifics of each of these 1D nanomaterials for gas sensing applications, their synthesis and deposition, sensing performance, and commercial development in the last 5 years. It highlights the scalability of one-step electrodeposition of CTC nanowires on prefabricated electrodes, at room temperature, and from solution in making gas nanosensors.